Truss cutting apparatus with two cutting stations



United States Patent Inventor Donald C. Menge Warren, Michigan Appl. No.670,146

Filed Sept. 25, 1967 Patented Dec. 1, 1970 .Assignee Troy SteelCorporation Warren, Michigan a corporation of Michigan TRUSS CUTTINGAPPARATUS WITH TWO CUTTING STATIONS 20 Claims, 11 Drawing Figs.

U.S. Cl ..143/6, 143/46 Int. Cl B27g 5/02 Field of Search 143/6,

[ 56] References Cited UNITED STATES PATENTS 823,506 6/1906 Cadorette etal. 143/6 834,206 10/1906 Kantner 143/6 1,481,569 l/1924 Tannewitz..l43/6(46)UX 1,808,453 6/1931 Koning l43/6(46)UX 3,026,917 3/1962Schwartz 143/6(46-)UX Primary Examiner-Donald R. Schran Artorneyl-lauke,Gifford & Patalidis ABSTRACT: A pair of spaced saw-supporting pedestalsare mounted on a frame for horizontal movement toward and away from oneanother. A section of unfinished lumber spans the two pedestals. Eachpedestal is rotatable about a vertical axis to individually position apower saw to cut the lumber at a selected pitch and a predeterminedlength. The apparatus includes a novel telescoping saw shield and anovel lumber clamp.

Famed Dec. 1,1970" 3,543,815

INVENTOR. DOA/4L0 C MENGE BACKGROUNDOF THE INVENTION i Y 1. Field OfTheInvention This invention relates to cutting apparatus for forming asection of unfinished lumber into an element for a prefabricated trussand more specifically to a cutting ap paratus employing a pair ofsaw-supporting stations, each station mounted on a frame for movementtoward and away from one another between positions corresponding to thelength of the finished truss element, and each station rotatable about avertical axis substantially intersecting the axis of the lumber so thattheir respective saws are positioned to cut the lumber at a selectedpitch.

2. Description Of The Prior Art Prefabricated, wooden building trussesrequire a series of interconnected precut wooden webs and diagonals. Theelements of each truss are normally precut, clamped together and nailedto form the finished truss.

A major problem confronting the fabricator of prefabricated trusses isthat each truss requires a number of webs and diagonals of differentlengths having its ends precut at different pitches. It is presentpractice to employ very sophisticated and expensive sawing apparatus inorder to form a section of unfinished lumber into a truss element.

It is the broad purpose of the present invention to provide an improvedcutting apparatus for forming truss elements which is formed from arelatively few inexpensive components into a versatile cutting apparatusand has a number of features permitting a single operator to form trusselements at a greater output than can be achieved by comparableconventional equipment,

SUMMARY The preferred embodiment of the present invention, which will besubsequently described in greater detail, comprises an elongated framehaving a track for supporting a pair of generally semicircularcarriages. The. carriages are movable toward and away from one anotherto positions accommodating the particular length of the finished trusselement.

Each carriage supports a clamping device and a saw-supporting pedestal.Each clamping device comprises a pair of cooperating jaw elements formedinto a substantially C- shaped configuration with the upper jaw elementspring loaded so that a section of raw lumber can be inserted throughthe open end of the clamp and seated on the lower jaw element. A sectionof unfinished lumber spans the two carriages and is supported in the twoclamping units. Other types of clamps may also be used.

Each saw-supporting pedestal is mounted on its carriage for rotationabout a vertical axis which intersects the unfinished lumber. A rotarypower saw isv supported on a pivotal arm mounted on each of thepedestals in such a manner that the saw can be lowered from a normallyraised position downwardly into cutting engagement with the unfinishedlumber.

' The saw engages the lumber at a pitch determined by the angularposition of the pedestal relative to the longitudinal axis of thelumber. A protractor is laid out on the carriage with indiciacorresponding to various angles of rotation of the pedestal. A pair ofstop members are clamped to the periphery of the carriage at positionscorresponding to the desired pitch of a double end cut truss element. Anarm extending radially from'the pedestal traverses the protractor andengages the secondchannel shaped guard is swingable about the axis ofseries of angular indicia. Thus during the setup operation the rotationof the blade between. retracted and extended positions with respect tothe fixed guard. When the saw is in its raised noncutting position, thesecond guard is extended and substantially encloses the cutting edge ofthe blade. A cable having one end fixed to the pedestal and its oppositeend connected to the movable guard retracts the movable guard:

within the fixed guard-as the sawis lowered to a cuttin'gposition. Asthe movable guard is retracted, a circumferentialsegment of the saw isexposed to engage the lumber. When the saw-supporting arm is raised fromits cutting position, the' movable guard extends from its retractedposition and encloses substantially all of the exposed cutting teeththereby providing an important safety feature.

The saw supporting arm is mounted on a pivot pin which can be positionedat a selected distance from the cutting area. This adjustment permits arelatively small diameter blade to accommodate different widths oflumber.

The pivot pin also permits the position of the saw-supporting arm to belaterally adjusted in order to adjust the cutting plane of the blade.

A chute is disposed below each cutting area and provides an easy meansfor collecting the cutoff sections of lumber hypermitting the lumber tofall of its own weight assisted by the draft created by the rotating sawblade. This eliminates blowers and conveyors which are normally utilizedwith conventional truss cutting apparatus.

It is therefore an object of the present invention to provide animproved cutting apparatus for preforming the opposite ends ofa woodentruss element.

It is another object of the present invention to provide a cuttingapparatus for sawing an unfinished section of lumber into a trusselement having its opposite ends cut at a predetermined pitch-byproviding a frame having a pair of saw stations mounted thereon forrelative movement toward and away from one another to positionsaccommodating thelength of the finished truss element, each of the sawstations being rotatable about a vertical axis to selected positionscorresponding to the desired pitch.

It is still another object of the present invention to provide animproved truss-cutting apparatus for sawing an unfinished section oflumber into a precut truss element comprising an elevated clampingdevice and an elevated saw-supporting pedestal having a power sawmounted thereon for movement toward cutting engagement with a section ofunfinished lumber supported in the clamping device and including chutemeans disposed below the cutting area for collecting the sawed offsections of lumber.

Another object of the present invention is to provide a trusscuttingapparatus having a cutting station including a saw-supporting pedestalmounted for movement about an axis to angular positions corresponding tothe desired pitch at which the unfinished lumber is to be cut andincluding stop means which are disposed in selected positions on aprotractor for defining the cutting positions of the pedestal.

Still another object of the present invention is to provide an improvedretractable guard means for a rotary saw blade supported for movementbetween a cutting position and a nonshaped guard and a movablechannelshaped guard, the mova- .blc channel-shapcd guard retracting intothe fixed channelshapedguard when the saw is moved toward a cuttingposition and extending from the fixed guard to enclose the cutting teethwhen the saw is moved toward a noncutting position.

Another object of the present invention is to provide an improvedclamping devicefor supporting a section of uncut lumber in atruss-cutting device.

Still further objects and advantages of the present invention willreadily occur to one skilled inthe art to which the invention pertainsupon reference to the following description,

DESCRIPTION OF THE DRAWINGS The description refers to the accompanyingdrawings in which like reference characters refer to like partsthroughout the several views and in which:

FIG. -1 is a perspective view of a cutting apparatus illustrating thepreferred embodiment of the present invention with parts of the chutesbroken away for purposes of description;

FIG. 2 is an enlarged perspective view of the-spring-biased meansemployed for maintaining the saw-supporting pedestal in a neutralposition;

FIG. 3 is a plan view of the preferred apparatus illustrating one of thesaw-supporting pedestals rotated in phantom between its alternatecutting positions;

FIG. 4 is an elevational view of the preferred saw-supporting pedestalillustrating the saw-supporting'arm in-its raised position with thetelescopic guard partially extended;

FIG. 5 is an elevational view of the preferred saw-supporting pedestalsimilar to FIG. 4, but with the saw-supporting arm in its loweredcutting position;

FIG. 6 is another view of the preferred saw-supporting pedestal with thesaw removed for purposes of the description; FIG. 7 is a plan view ofthe preferred saw-supporting pedestal with the power saw removed;

FIG- 8 is an enlarged perspective view of the preferred lumber-clampingdevice;

FIG. 9 is a view illustrating alternative cuts that can be made bylaterally positioning the saw and its supporting pedestal;

FIG. 10 is an enlarged view taken along the line 10-10 of FIG. 5; andangle; and

FIG, is an enlarged cross-sectional view taken substantially on the line11-11 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, thepreferred cutting apparatus is illustrated in FIG. 1 as comprising anelongated frame 10 having a pair of spaced parallel horizontal trackmembers 12. A pair of cutting stations 14 and 16 are mounted on theframe 10 and are movable along the track toward and away from oneanother. Preferably the cutting station 14 is releasably clamped on theframe 10. and the opposite cutting station 16 is movable relative to thecutting station 14 to a position accommodating the length of a finishedtruss element 18 which spans the two stations 14 and 16.

The cutting stations 14 and 16 are similar to one another except for arightand left-hand relationship and with a few other exceptions whichwill be noted. Preferably the cutting gage the lips 29A of the channel.The stop 26 is clamped between the head of the bolt 29D and the T-shapedmember 298 in an upright position. Rotation of the bolt 29D in a reversedirection loosens the member 298 and nut 29C to permit the operator toreposition the stop 26. The stop 28 is similarly clamped to itsrespective channel. I

A protractor 30 is formed around the periphery of the carriage 22 of thestation 14 and a protractor 32 is formed around the periphery of thecarriage 22 of the station 16. The protractors 30 and 32 comprise aseries of indicia'formed in graduations around. the center of each ofthe carriages 22. The protractor '30 on the work station 14 preferablyhas indicia formed at regular intervals from 10 and increasingin acounterclockwise direction to 170. The protractor 32 of the work station16 preferably has indicia laid out in regular intervals and increasingfrom 190 in a counterclockwise direction to 350.

A clampingdevice 34 is mounted on each of the carriages 22. The clampingdevices 34 support the unfinished lumber 18 for a downward cuttingengagement with a power saw. Referringto FIG. 8, each clamping device 34includes an upright support 36. An L-shaped lower clamping jaw 38 isfixed to the upper end of the support 36 and has an upwardly directedside section 40. A horizontally extending threaded pin 42 is fixed tothe side section 40 and receives an upper L-shaped jaw member 44 havinga downwardly depending side section 46 which is normally in face-to-facerelationship with the side section 40 of the lower jaw member. The upperjaw member 44 has a vertical slot 48 which is received by the pin 42. Anut 50 carried on the pin 42 retains a spring bias member 52 which actsagainst the downwardly depending side 46 of the upper jaw member tomaintain the horizontal section of the upper jaw member in a horizontalposition so that the upper jaw member 44 and the lower jaw member 38form a substantially C-shaped clamping means.

A guide member 53 is fixed to the lower jaw 38 in alinement with thehorizontal portion of the lower jaw. The guide .member 53 assists theoperator in placing the unfinished lumber in the clamp.

This clamping arrangement permits the unfinished lumber to be insertedthrough the open'mouth of the C-shaped clamping means and seated on thelower jaw in abutment with the upwardly extending side 40. The yieldableupper jaw permits the operator to quickly seat the unfinished lumber inposition and to remove the finished truss element from the two clampingdevices 34. The preferred clamping devices 34 also prostations 14 and 16face in a common direction to enable the operator to position the lumberand do the required cutting from one side. I

As can best be seen in FIG. 3, a linear scale 20 is defined on the frame10 between the tracks 12, and a pointer 21 is mounted on the cuttingstation 16 to assist the operator in positioning the cutting stations 14and 16 at a distance determining the length of the finished trusselement 18. Thus in the preferred embodiment, the unfinished lumber canbe double end cut to a length as short as 20 inches and as long as maybe desired, limited only by the length of the frame 10.

Each of the cutting stations comprises a substantially semicircularcarriage 22 slideably mounted on the track elements 12. Each of thecarriages 22 has a channel-shaped peripheral member 24. A pair of stops26 and 28 are clamped to the channels 24 at selected positionscorresponding to the pitch at which the ends of the truss element 18 areto be cut.

' FIG. 11 'illustrates the manner in which the stop 26 is clamped inposition. The channel 24 has a channel-shaped cross section including apair of inwardly directed lips 29A. A T-shaped member 298, a nut 29C,and a bolt 29D cooperate to releasably clamp the stop 26 in position. Byrotating the bolt in one direction. the member 298 and nut 29C tightlyenvide a rigid support for the lumber for a downwardly moving cuttingblade.

Referring to FIGS. 4, 5, 6 and 7 for a description of the preferredcutting station, each of the cutting stations comprises a channel-shapedarm 54 which is rotatably mounted on the carriage 22. A horizontal angle58 is mounted'at the upper end of the pedestal 56 and carries a pair ofhorizontally extending parallel arms 60. The arms 60 extend from theangle 58 toward the center of rotation of the pedestal 56 and each has aseries of pin mounting holes 62.

An elongated pivot pin 64 is journalled in a selected pair of mountingholes. A saw-supporting arm 66 is pivotally mounted on the pivot pin 64and is movable between raised and lowered positions. FIGS. 4 and 6illustrate the saw-supporting arm 66 in its raised position and FIG. 5shows the arm 66 in its lowered position. The saw-supporting arm 66moves between its vertical positions toward and away from the clampingmeans 34.

An elongated spring 68 having its lower end anchored to the arm 54 andits upper end connected to an arm 70 carried by the pivot arm 66 tonormally maintain the pivot arm 66 in its raised position. The arm 70 isbiased downwardly until it abuts the angle 58.

Referring to FIG. 7, the saw-supporting arm 66 has a width less than thelength of the pivot pin 64 between the arms 60 thereby permitting thearm 66 to be laterally adjusted between the fixed supporting arms 60. Aplurality of spacers 72 mounted on the pivot pin 64 position the arm 66in place to accommodate the particular cut that is to be made.

A power saw 74. is mounted on each of the arms 66. Each saw 74 has arotary cutting blade 76 which engages'thc lumber when the arm 66 islowered toward its horizontal position. Thus it can be seen that thecutting plane of the blade 76 is defined by the position of the arm 66on the pivot pin 64. The cutting engagement between the blade 76 andtheunfinished lumber is defined by the selected pair of apertures 62 inwhich the pivot pin is seated. This position is determined by a numberof factors including the diameter ofthe cutting blade 76, thecross-sectional dimensions of the lumber 18 and the particular pitch atwhich the unfinished lumber is to be cut.

Referring to FIG. 2, the inner end of each arm 54 is attached to ahousing 78. A journal 79 depends down from the housing and is rotatablymounted in a bearing 80 carried by a bearing holder 8l'carried by thecarriage 22. The bearing 80 permits the arm 54 to be easily rotatedbetween cutting positrons. A pair of pins 81A depend from the housing 78and are connected by springs 818 to a pin 81C fixedly mounted oncarriage 22. The springs 81B are arranged on opposite sides of thejournal 79 so that rotation of the arm 54 in one direction extends oneof the springs and rotation in the opposite direction extendstheopposite spring. Thus an arm 82 which extends at right angles fromthe housing 78 relative to the arm 54 assumes a neutral position whenany external forces on the arms 54 and 82 are released so that thesprings assume a balanced condition. ln' this neutralposition, the arm82 is generally alined with the longitudinal axis of the frame 10 (asparticularly seen in FIG. 3) with the saw 74 swung into a positionpermitting the operator to readily insert and remove the unfinished andfinished lumber from the clamping devices 34.

The arm 82 extends beyond the periphery of the carriage 22 so that whenthe pedestal is rotated away from its neutral position, the arm 82 movesinto abutmentwith one ofthe stops 26 or 28. As heretofore described, thestops 26 and 28 are clamped in positions corresponding to the selectedpitch angles. Swinging the pedestal toward and into abutment-with thestop 28, the operator lowers the saw-supporting arm 66iuntil the sawengages the lumber in a cutting relationship. The operator then releasesthe saw which is automatically raised under the influence of the spring68 out of engagement with the lumber 18. He also releases the arm 82 sothat the pedestal swings to its neutral position. The operator thenswings the pedestal in the opposite direction until the arm 82 abuts thecompanion stop 26, lowers the saw and completes the second cut on theend of the lumber 18. This sequence of steps is then performed at thecutting station 16 to form the opposite end of the truss element 18.

Normally the operator is given four individual angles for setting up themachine so that when he positions the stops 26 and 28 of each of thecutting stations, there is no chance of clamping the stops in the wrongposition. This is because a different set of indicia is associated withthe protractor 30 than is associated with the protractor 32. This isopposed to a system wherein each ofthe protractors has a similar setofindicia.

It can also be seen that the cutting blade 76 normally engages theunfinished truss element 18 closely adjacent the longitudinal axis ofthe lumber in a downward cutting stroke and closely adjacent theclamping device 34 so that the lowerjaw 38 provides a maximum support. i

A chute 84 is carried by each of the upright pedestals 56 below thecutting area so that the sawed off sections of lumber are collected asthey fall. In addition, the rotating blade 76 creates a downwardlydirected draft which helps to deliver the sawed off portions of lumberinto the chute 84. A'barrel 85 or other suitable container can bepositioned to receive the scrap from the chute 84.

lt is obvious that the lengthof cut obtained 'on a truss element isrelated to the diameter of the cutting blade. Referring to FIG. 9. whenit is desired to form a truss element having an end with a single cutsuch as at 86, the center of rotation of the cutting blade is generallyin vertical alinement with the longitudinal axis of the truss element18. Where a double-ended cut is to be made, the positionof the cuttingblade 76 can be adjusted by positioning the saw-supporting arm 66 on thepin 64 so that the center of rotation of the cutting blade is offsetfrom the longitudinal axis of the truss element 18 to provide an initialcut at 88 and then a second cut as at 90 in the second position of thepedestal 56.

In order to achieve an end cut with a very high pitch, that is to saywhere the cutting plane of the blade forms a relatively acute angle withthe longitudinal axis of the truss element l8, thereby requiring asubstantially long cut, or when the lumber is of excessive width, acutting blade having a relatively small diameter can providesuch a longcut in a two-step process by first sawing half of the cut at onestation, turning the truss element 18 end-for-end and forming the secondhalf of the cut at the opposite station.

Referringto FIGS. '4, 5 and 10. the saw 74 has a novel form oftelescopic guard means for protecting the operator from an accidentalexposure to the cutting edge of the blade 76 as the saw 74 is raisedbetween cutting and noncutting positions. A fixed, arcuate,channel-shaped guard 92 encloses the upper half of the circumferentialedge of the blade as it rotates. A movable, channel-shaped guard 94 istelescopically engaged within the fixed guard 92 and is swingable aboutthe axis of rotation of the blade 76. A wire 96 has one end connected toan arm 97 extending from the upper end of the movable guard 94 and itsopposite end anchored to the horizontal angle support 58. The loweranchored end of the wire,96 is on the side of the pivot pin 64 oppositethe position of the saw 74 as it pivots between its raised and loweredpositions. Thus as the saw is lowered from its raised position,illustrated in FIG. 4, the wire 96 causes the movable guard 94 toretract within the fixed guard 92 thereby exposing a sufficientcircumferential segment of the cutting blade 76 to engage the lumber 18in a cutting relationship. Similarly, when the saw 74 is raised from itscutting position, the movable guard 94 extends from within thefixedguard and encloses a substantial portion of the exposed-cuttingperiphery of the blade76 thereby protecting the operator fromaccidentally coming into contact with the rotating blade.

Preferably each of the saws 74 is provided with an elongated handle 98with a rubber grip 100. The handles 98 permit the operator to lower andraise the saws 74 without coming into close contact with the saws. g r

A taut, overhead line 102 supports the electrical cords 104 of the saws74 on awning pulleys 106 so that the saw carriages can be moved towardand away from one another without interference with the cords. t

Referring to H6. 1, a hand-operated C-clamp 108 provides means forholding the arm 82 rigidly in one position where asingle cut of the samepitch is to be made on the same end ofa series of truss elements.

In conclusion, I have described an improved cutting apparatus for sawingwooden truss elements such as webs and diagonals. Preferably thesemicircular carriages 22 have a diameter of about 3 feet, therebyassuring a high degree of accuracy in positioning the-stops 26 and 28.The length of various size truss elements can be readily accommodatedbecause the longitudinal cutting stations 14 and 16 can be quicklychanged on the frame 10. Normally the saw station 16 is movable theentire length of the track 12 and clamped in position by a quick-actingeccentric clamp (not shown) for speed and ease of operation. The sawstation 14 is normally moved only short distances about 3 inches tocompensate for changes in the lateral position of the saw on the pin 64.Any double end cut that is necessary for any conventional web member canbe achieved with an S-inch diameter saw regardless of the pitch merelyby changing the position of the pivot pin 64 on the arms 60 therebymoving the saw toward a longer desired cut. By spring mounting both thesaw-supporting arm 66 and the saw-supporting pedestal 56, the operatorcan quickly remove and insert the lumber without being concerned aboutthe position of the moving components of the apparatus. The chute ispreferably formed of sheet metal and collects the debris without thenecessity for blowers or conveyors which are usually necessary forconventional truss cutting apparatus.

his to be understood that although i have described the preferredembodiment of my invention in its simplest terms, various changesandrevisions can be made therein without departing from the spirit ofthe invention or the scopeof the appended claims.

Iclaim:

l. Cutting-apparatus for shaping the end of an elongated work piece,comprising: I

a. a frame;

b. support means said frame;

c. first cutting means mounted on said frame for cutting engagement withsaid workpiece, said first cutting means being infinitely anguiarlyadjustable about an axis to engage said workpiece at a selected angle;and

01. second cutting meansmovably mounted on said frame for cuttingengagement with said workpiece, said second cutting means beinginfinitely angulariy adjustable about anaxis to engage said workpiece ata selected angle, said second cutting means being mounted for movementbetween selected cutting positions toward and away from saidfirstcutting means; and means normally urging said first and said secondcutting means into a neutral position other than said selected angles.

l-The cutting'apparatus as defined in claim 1, including scale means onsaid frame for indicating the distance between the engagement of saidfirst and second cutting means with said workpiece.

3. The cutting apparatus as defined in claim 1, including firstprotractor means mounted on said frame for indicating the angulardisposition of said first cutting means relative to said workpiece, andsecond protractor means mounted on said frame for indicating the angulardisposition of said second cutting means relative to said workpiece. I

4. The cutting apparatus as defined inclaim 3, wherein said firstandsecond protractor means each have an individual series of indiciaassociated with the angular disposition of their respective cuttingmeans. r

5. A cutting apparatus as defined in claim 1, further comprising apedestal rotatably mounted on said frame; a pivotal support arm mountedon said pedestal; said cutting means comprising a saw mounted on saidpivotal support arm for movement toward and away from cutting engagementwith said workpiece, and including a position-defining arm fixediycarried by said pedestal and extending radially from the axis ofrotation of said pedestal; a stop adjustably mounted on said frame in aposition corresponding to a selected angle of engagement between saidsaw and said workpiece, said stop being disposed in the path of rotationof said position-defining arm and abutting said position-defining armwhen said saw is in said selected angle ofengagement.

6. The cutting apparatus as defined in claim 5, including a second stop,said first mentioned stop and said second stop being mounted in selectedpositions on a graduated scale, and on opposite sides of a neutralposition of said position-defining arm.

for positioning an elongated workpiece on pivotal support arm is mountedfor movement between raised and lowered positions, and including biasmeans for normally urging said pivotal support arm toward a raisedposition so that said saw is spaced from said workpiece, said bias meansbeing yieldable to a pulldown force for lowering said saw into cuttingengagement with said workpiece.

8. The invention. as defined in claim 7, including clamping means forlocking said position-defining arm in a position spaced from saidneutral position.

9. The cutting apparatus as defined in claim 5, including chute meansmounted on said pedcstai below the area of cutting engagement of saidsaw with said workpiece.

7. The cutting apparatus as defined in clairn 5, wherein said circularcutting blade, said pivotal arm being vertically mova- I ble toward andaway from a lowered position wherein the cutting edge of said bladeengages a workpiece, and means for retracting said movable guard withinsaid fixed guard to expose the cutting edge of said blade as saidpivotal arm is lowered. 7

- 11. Cutting apparatus for shapingthe end of an elongated workpiececomprising:

a. a frame; u

b. workpiece support means mounted on said frame;

c. saw-supporting means mounted on said frame and rotatable about anaxis, said saw-supporting means including a pivotal support arm;

d. a saw mounted on said pivotai support arm for movement toward andaway from cutting engagement with a workpiece mounted on said supportmeans;

e. a position-defining arm carried by said saw-supporting means andextending radially from the axis of rotation of said saw-supportingmeans; and

. a stop mounted on said frame for infinite adjustment between positionscorresponding to selected angles of engagement between the cutting edgeof said saw with said workpiece, said stop being engageable with saidpositiondefining arm when said saw-supporting means is rotated aboutsaid axis.

12. A cutting apparatus as defined in claim ll, including bias meansnormaliy urging said saw-supporting means toward a neutral position withsaid position-defining arm being spaced from said stop.

13. The cutting apparatus as defined in claim 12, wherein saidposition-defining arm traverses a graduated scale when saidsaw-supporting means is rotated.

14. The cutting apparatus as defined in claim 12, inciudi'ng a secondstop, said first-mentioned stop and said second stop being infinitelyadjustably mounted in selected positions on a graduated scale and onopposite sides of the neutral position of said position-defining arm.

. 15. The cutting apparatus as defined in claim 11, wherein saidsaw-supporting means comprises:

a. a pedestal mounted on said frame and rotatable about said axis; and

b. means for adjustably mounting said pivotal support arm on saidpedestal at aselected distance from the longitudinal axis of saidworkpiece so that said saw can be raised and lowered about a selectedpivot point in an arc of 1 cutting engagement with said workpiece.

16. The cutting apparatus as defined in claim 15, wherein saidlast-mentioned means comprises:

a. a pivot pin;

b. means for journalling said pivot pin on said pedestai at a selecteddistance from the longitudinal axis of said workpiece; and

c. said pivotal support arm being mounted on said pivot pin formovemen'tbetween raised and lowered positions.

17. The cutting apparatus .as defined in claim 16, including resilientbias means acting on said pivotal support arm for normally urging saidpivotal support arm toward a raised position, said resilient bias meansbeing yieldable to apulldown force for lowering said saw into cuttingengagement with said workpiece.

18. The cutting apparatus as defined in claim 16, wherein said sawincludes a rotatable blade and the position of said pivotal support armon said pivot pin is adjustable in directions perpendicular to the pianeof rotation of said rotatable blade.

9. The cutting apparatus as defined in claim 13., including chute meansmounted on said saw-supporting means and below thecutting engagement ofsaid saw with said workpiece for receiving sawed-off portions of saidworkpiece.

. 20. In combination, a support, an arm pivotably mounted on i saidsupport for movement between first and second operative positions, a sawhaving a rotating blade with a circular cutting movement toward and awayfrom a lower cutting position wherein said circumferential segment ofsaid cutting edge engages aworkpiece. said cutting edge being movablealong said arcuate path, a flange carried by said second channel-shapedguard and movable therewith; said flange being axially dispjaced fromsaid second channel-shaped guard outside ofsaid first channel-shapedguard, a wire connecter having one end fixed to said support and spacedfrom the pivot point of said arm in a direction opposite to the movementof said arm as said arm is pivoted toward said lower cutting position.the opposite end of said wire connecter being attachedto said 7 secondguard flange, said wire connecter restraining move ment of said flangealong said first-mentioned arcuate path r such that said flange followsa second arcuatc path different from said first-mentioned arcuatc pathso that said second channel-shaped guard is retracted within said firstchannelshaped guard by means of the restraint of said wire connecter assaid saw is lowered toward said lower cutting position,

whereby said enclosed and shielded circumferential segment of saidcutting edge is exposed.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,543,815 Dated December 1, 1970 Inventor(s) Donald C. Menge (TSC-1Q7-A)It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 3, line 34, after f5; delete "and angle:"

Column 7, line 70, change "7 to -6- tcgaiifl FEB. 9,1971

(SEAL) M MlFletch rJ mm B. SGHUILER, J1

Amafing Officer Col-13:10am: of Patent1

